2013 Was A Breakthrough Year For Nuclear Diplomacy

And as the hours are counted down towards the end of 2013, we're looking back at some of the stories that helped define the year that was. And one of the most significant moments this year - after years of resisting, Iran reached an agreement with the U.S. and other world powers to suspend much of its nuclear activity.

There were plenty of doubts about the agreement early on, but now experts expect it to be implemented over the next six months. More difficult talks still lie ahead as international leaders press for tangible assurance that Iran is not seeking a nuclear weapon

NPR's Peter Kenyon has this report.

PETER KENYON, BYLINE: This was the year journalists covering the Iran nuclear issue got to write that rarest of all sentences: They have a deal.

More of a time-out than a finished agreement, really, but a breakthrough for nuclear diplomacy nonetheless. It sets the stage for the real test - hammering out a comprehensive accord intended to confirm the peaceful nature of Iran's nuclear program and to return Iran to the global economy with the lifting of international sanctions. There have been snags - Iran cut off expert level talks briefly after Washington announced new enforcement actions based on existing sanctions. But even so, inspectors from the International Atomic Energy Agency have visited Iran's heavy water reactor at Arak, and the agency has its own agreement with Iran for more visits to the country's three main nuclear facilities, and to other sites such as uranium mines. Tariq Rauf, former head of verification and security for the IAEA, says an important step should be completed within 90 days - the so-called downblending of Iran's 20 percent enriched uranium, the closest it has to weapons grade fuel. It will be diluted to below 5 percent purity, which is suitable for nuclear power generation.

TARIQ RAUF: So the downblending has to be accomplished within three months of the start of the clock on the Geneva deal. The visit to Iraq and the heavy water plant has already taken place. And then the daily visits to the three facilities, plus the normal safeguards activities that the IAEA has been carrying out in any case.

KENYON: These early steps, plus some easing of sanctions, are crucial, says analyst Ali Vaez with the International Crisis Group. These small successes will help keep positive momentum going during what he expects to be extremely difficult talks on a comprehensive nuclear agreement.

ALI VAEZ: The two sides are as far apart as one can imagine. There's a huge gulf between the two sides on every single element of the final deal. You know, what to do with Iran's heavy water reactor, what to do with Iran's Fordow facility, it's a bunker facility. And on the Iranian side, I would add, what are the sanctions that are going to be lifted, not only suspended but permanently lifted?

KENYON: Longtime arms control expert Robert Einhorn, speaking at an event organized by the Center for Strategic and International Studies, agreed that talks on a comprehensive deal will be thorny. For instance, the plan agreed to in Geneva speaks of a mutually agreed enrichment program for Iran, consistent with its practical needs. But Einhorn says Tehran will be dismayed at just how minimal a program the international side, known as the P5+1, is likely to propose.

ROBERT EINHORN: Now, the way the P5+1 governments view those practical needs is very limited. They have a research reactor in Tehran that already has enough fuel for a few decades. And they have a power reactor at Bushehr that the Russians provide fuel for - they don't need any fuel for that. On the drawing board they have some other research reactors planned, but they haven't broken ground on them. For the foreseeable future they have very little practical need.

KENYON: That's not how Iranian officials see it. They regularly tout plans for new reactors and new power plants, and insist that enriching their own uranium is a right that they will never abandon. Verification will be one of many crucial and difficult aspects of a final agreement. Tehran will need to agree to even more intrusive verification measures if it wants oil and banking sanctions lifted, which will underscore the uncomfortable fact that of all the signatories to the Nuclear Non-Proliferation Treaty, Iran is the most inspected country on earth. Geneva-based Iranian analyst Shahram Chubin suggests that any tough new inspection regime should be pitched as the new state of the art in non-proliferation.

SHAHRAM CHUBIN: Any inspections that are intrusive should be dressed up as a model for everybody else. In other words, the Iranians have always argued, you know, that you can't single us out. This should then be a model for everybody else.

KENYON: Waiting in the wings will be hardliners in Iran, in Israel, and in Congress, where a push for new sanctions is already underway. Peter Kenyon, NPR News, Istanbul. Transcript provided by NPR, Copyright NPR.